Doesn't print the right colours in some programs

[Gkras]

Hello,

On my job we have a HP Designjet 500 (it is an older model)

So far I got the printer working and it does print on the right size of paper.

Now the only thing that is a bit weird with me is that the prints are sometimes weird.

If I would print an image from a .DWG program (see image 1) I will got some weird lines in the drawing.

The orange/yellow lines supposed to be red, and the blue lines should be clear blue and not different kind of shades.

And if I would convert the .DWG to an .PDF, I only have the black, and yellow colours.

And if I would make a print from an .JPG file I would get the right colours. (image 2)

I replaced the printheads of yellow and black, tried to allign the printhead.

So far that is the problem. I hope someone could help me.

[Gkras]

I also tried to print on greyscale but then I got green lines in it.

The rest of the drawing is in black and grey, but everything that is supposed to be red or blue has those green/yellow lines in them